Rollins has hit a fly ball on the infield 31 times in 2012. (Atlanta's Dan Uggla is second in the league with 21.) That equated to 20.1 percent of his batted balls entering Wednesday that ended as pop-outs. His career average is 11.2 percent.
The 20.1 percent clip is also highest in the majors among qualified hitters.
"That's just one of those things," Manuel said. "That's just one of those years."
The shortstop has shown flashes of offense in 2012. Mostly, his season totals produce a confusing line. His slugging percentage is its highest since 2009. His on-base percentage is its lowest since 2009.
Is there a correlation? Is Rollins swinging for the fences too often?
"I don't think he's trying to," Manuel said.
The manager has seen Rollins make a concerted effort to lay off pitches high in the strike zone. Still, the bad habit persists, and that leads to many of the pop-outs.
Rollins is in the first year of a four-year, $38 million contract. He turns 34 in November.
"In the last three or four years," Manuel said, "his offensive performance is coming down. The older he gets, that can be expected. He plays a very important position. He's in on a lot of action. He plays a lot of games."
Rollins, of course, still offers top-notch defense at shortstop. His manager plans on resting Rollins with more regularity in the season's final eight weeks. But can there be offensive improvement with age?
"Not unless he has a big year," Manuel said.
Cleveland released lefthander Jason Knapp, a former Phillies prospect once viewed as the centerpiece in the 2009 Cliff Lee trade. Knapp, 21, has not appeared in a game since 2010 and has undergone numerous shoulder surgeries.
In 2010, Baseball America rated him as the 64th best prospect in baseball.
The Phillies also traded catcher Lou Marson, infielder Jason Donald, and righthander Carlos Carrasco in that deal. Marson is the only one on the Indians' roster.
The Phillies will not have an idea on Placido Polanco's availability until he takes ground balls, which did not happen Wednesday. Polanco did play catch.
"We'll wait and see," Manuel said. "Some days it's better than others. Some days it feels good, and then all of a sudden he keeps feeling pain in his lower back."
Kevin Frandsen started his 10th straight game at third base.
The morning after pitching a shutout, Cole Hamels helped dedicate a new playground at Taylor Elementary in Hunting Park. A $300,000 grant from the Hamels Foundation enabled its construction. Team president David Montgomery attended the ceremony. . . . After a day off Thursday, the Phillies will face three St. Louis righthanders - Kyle Lohse, Jake Westbrook, and Lance Lynn.
Contact Matt Gelb at firstname.lastname@example.org or follow on Twitter @magelb.